<B>Block:</B>
355 cid 4 bolt block
Forged TRW flat top's
Molly race rings
Sportsman - II 2.02/1.60 (243 CFM at .600)
SLP Cam - 280/288 .502/.510 112 lsa
Full roller rockers, roller lifters
21"x7"x1.5" Perma-cool oil cooler
8.96:1 Compression Ratio w/ 72cc chambers

<B>Induction:</B>
1205 Ported edelbrock Base
Ported SLP runnes, siamesed tops
Ported fully siamesed plenum
Vortech V1 A-trim 720cfm (8psi) @ 65% efficiency
Holley Water/Alky injection
32d timing at 3,000rpm and above (with water, 26d w/out)
36# SVO injectors, 55psi WOT (50 psi idle)
1227749 ECM running $58 code
MSD 6AL w/ rev limiter

<B>Exhaust</B>
1 5/8 headers w/ 1404 gasket
Carsound cat
3" Hooker cat-back


I think this should be good for 520-530hp at 6,000rpm. The only "quirk" is the A-trim with the 3.33 pully. I think an S-trim would really help me out. Maybe a 255lph to replace the 155lph pump. Opinions?

 

Wow. I'm surprised noone here has any opinions.

-- Joe

 

Blown TPIs aren't really my bag, but I'll offer this up.... the Sportsman II heads have a WEAK exhaust port- no better than stock really. That's not what you want for a forced induction application. You want an exhaust port that flows like Niagara Falls.

The rest of it doesn't look too bad to me. I'll leave the fuel pressure and chip tuning up to you. Assuming it's done right it should make quite a bit of power.

Do you think you really need a blower that big for the rather modest RPM level you'll be turning?

 

I need a bigger blower than the A-trim. THe a-trim was designed for stock cars in the 220-240hp range (before charging). this thing is just bad. An S-Trim at 50,000rpm should work nicely.

I'm planning on shifting just over 6k. That should be good for a 124mph 1/4 run, or deep into the 11s.

-- Joe

 

500-545hp (crank) is possible with an A-trim, but you're trying to do it the hard way with that combination. First, I'd say that you're wasting your time upgrading the intake side like you did… stock TPI would have been sufficient as long as you were willing to build the power at a lower rpm, and the stock intake pieces don't really flow any worse then the intake side of those heads.

The exhaust side is completely inadequate though. At a minimum I'd be looking at doing a lot of work to the exhaust side of those heads, more exhaust duration and most likely a greater LSA. The headers may or may not be sufficient, depending on which ones they are and what you do with the cat back… I doubt that you'll be successful with the cat and the hooker cat back, almost nothing in that combination flows enough not to be a restriction, and any restriction will compound the fact that you're at the end of the blower's useful range. Improving the intake will also hurt your chances since you'll need to keep the blower above about 6psi boost to keep it in it's efficiency range and a better flowing intake will make that more difficult to do.

A 155l/h pump will not supply the needed fuel at the raised pressure, the pressure differential between idle and WOT should be max vacuum + boost (I'll bet that it will be in the 15psi difference range) and the injectors are marginal at best for that power range.

 

Really? when I spoke with a couple guys at vortech they laughed and sayd 450-480 was about max.

Stock tpi flows like 218 cfm. Those heads flow like 243. They are a
FELPRO 1205 port, stock TPI is almost a half inch smaller.

The exahust flows around 164cfm. What would you recommend to be a target number?

As far as the cat and cat-back goes, It wouldn't be an option for a Police Officer to not have Cat..

I thought it would keep the blower from taking more HP to produce the same amount of airflow (cfm)

-- Joe

 

Well, I'm just an opinionated pain in the *** looking at compressor maps for the thing (which has a standardized compressor head). Unless that compressor map is complete BS you should be able to get into that range without much problem, assuming that you build the engine to match the range that it works well in. Spin it to 50K and you'll actually get less flow then you would at 30K, but that's also a matter of getting the rest of the combination right and some finicky tuning. The combination that you described at the top will probably max that compressor out at about 440-450hp.

Yes, and the tpi base has a crappy port entry angle which causes the large port opening to act like a much smaller one. FWIW, I don't think that I've ever seen a stock tpi flow over 210 per runner (most are in the 200-210 range), but I suppose that 218 would be in the margin for error going from flow bench to flow bench. As long as you keep the intake port crossection appropriate you will see power increases with a stock TPI with intake ports into at least the mid 230-low 240cfm range.

To be honest, I wouldn't have chosen the Sportsman II's… I don't really see any advantages with using them over the typical, decent oem 350 head with minor cleanup besides that you're starting with fresh castings.

For the cam you listed I'd like to see something that hits 210-220cfm at least .050" before your peak lift that doesn't stall till well after that. I know, easier said then done. The more you fall short of that the more exhaust duration you need and the more lobe separation you need. If you actually go after getting those kinds of numbers, find someone that will try to get them by messing with the throat area of the port as little as possible. The trick to making this work is to keep the velocity very high through that area while finding most of the flow with the valve job, blending the valve seats and bowls.

Hum… interesting screen name for a cop. I'll assume that you're nothing like local cops.

Understood on the cats… do what I did on my 83 TA… custom dual cat setup, with high flow cats (I started with the headman ľ length headers). There's room for 2 full size cats in the lump on the passenger side without loosing ground clearance, for your combination I'd bother with the hassle of 3" tubing from both sides and 3" carsound cats (probably the best flowing cats on the market), but dual 2.75" or even 2.5" mandrel bent stuff if done well will work (you'll find that the better 2.5" and 3" cats use the same beads, so just get the matching tubing size). I found that running a crossover between the 2 sides as close to the engine as possible both tones the exhaust down and gives you a little extra power (mine was right at the bend by the starter). After that I used a flowmaster y and 3" over the axle pipe. I ran this setup with no muffler at all for a long time and it was reasonably quiet (as in well below legal limits and quieter then the average semi open borla or mufflex 4"). Add something like a dynomax welded muffler (go through the part numbers, there's a bunch of 3"/3" ones that flow significantly more then the others) and it will be very mellow, stockish sounding idle and only sounding serious at WOT.

compressor maps are funny things. Remember that the design that they are using was originally developed for turbochargers used mostly on diesel engines. They actually get less efficient at lower and higher pressure levels and more efficient at moderate levels. Get the intake flowing too well and you'll get less power out of the same blower just like if it doesn’t flow enough.

 

Thats an interesting point. I'm spinning it to 50k which produced around 8psi on the gauge. Thats with a 3.33 pully. I have a 3.45 as well I can try.

Hrmm. So your saying an almost stock setup would be better than a fully ported high flowing setup?

Because it's a cheap high flowing performance head. It outflows most any fully ported l98 head in stock form. The magazines and engine builders like it.. ??

I'm gonna get some runs in with the 3.33, and 3.45 pullys. Then change out the runners/plenum to stock and get some runs in with both pullys on that setup and see what the differences are.
If infact the stock runners/plenum make more power, I'll sell the SLP's.


Whats your setup look like?

 

I'd be very interested in seeing the results of that, it would verify the accuracy of their published maps, which show a fairly steep decrease in mass flow and efficiency above 35K rpm, and doesn't even show numbers over 40K rpm.

a stock intake has sufficient flow for just about 400hp NA (assuming that you can get the engine to breath that much within the intakes tuned rpm range) and heads that flow in excess of that mated to a blower that is capable of 500-550hp worth of air flow in the 1.4-1.6 pressure ratio range (about 5.5-9psi boost). You want to build the engine to pose just enough of a restriction to get the boost level in that range while allowing that amount of air in. The combination that you're describing should be able to breath pretty close to 600hp worth of air at that pressure, which will just result in the whole combination seeing less boost and dropping into a much less efficient range on the compressor map. You might still luck out since your boost pressure will still be higher then your intake parts would suggest because of insufficient exhaust flow.

Do a search on me and L98 heads… hell, don't worry about it, I'll tell you what I've said: they are the worst flowing 350 heads around. I don't know of worse. Get any set of OEM 350 heads (say, the every common, crappy 882s) with a decent, stock valve job and you'll instantly gain 30cfm or so on the intake side. Blend that valve job into the bowls a little, remove any nasty spots that are left and you'll have something that flows what your sportsman's do.

Magazines base their opinions on what their advertisers tell them they are. Engine builders like them as a stock replacement that avoids the hassles of starting with questionable, lightweight castings if their customers are willing to pay for them.

I'm not sure that that's going to be enough of a pulley change if you're really spinning it to 50Krpm. Second, what I'm saying is only true if you intend to stay with the small head unit. If you were to upgrade the head unit some of this changes. I'd still tell you that your exhaust needed to be upgraded (and appropriate cam chosen for your exhaust port flow). Once the exhaust was upgraded I'd suggest that the next step would be to do something with the manifold base. With an s trim you'll still have something that will loose efficiency at higher rpm's, but a t or ys does not (within reason, say to 50-55K or so).


I just sold off one car and parted out the '83 Crossfire TA and had the carcass towed away. The next project will be built up in my '87 Formula 350 and then swapped into whatever replacement body that I eventually find (it's an Indiana car which is rotting out from underneath and has a bent frame). It's due for emissions this month so I'm planning on running down to the garage after this and digging through my pile of exhaust parts for a cat. Once that hassle is done it's getting a holset turbo off of a Cummins 6CT out of a Kenworth semi/wrecker which will either make it go faster or break ****, probably both.